uh-oh ... burned valve?

Post by **erikv11** » 30 Oct 2010, 12:15

96 855 NA, 200k miles

While I was out of town this week my wife was driving on the freeway and the car started throwing p0301s with flashing CEL. She reset the CEL but it comes back on after a couple miles. Car runs rough under all conditions but is certainly driveable.

Today I looked at it. From pulling wires I can see that #1 is not firing. New plugs (2 weeks), older cap and wires, but ignition is probably not the issue anyway. Also almost for sure the engine has leaky valve stem seals, with #1 the worst (pics of plugs with oil deposits), another reason I interpret burned valve.

Compression is 0-195-200-185-200 so I presume this indicates a bad valve. And not just stuck but burned, because compression is basically zero.

Here are some questions I have

1) any other opinions, besides burned valve? Should I try something to unstick the valves (and what should I try)?
2) is it even worth doing a leak down test (I have the tools) since the head has to come off no matter what?
3) if it is a valve, I'm assuming a rebuilt head is the way to go rather than something like valve job plus valve stem seals?
4) Can I limp 3 miles back and forth to work on only 4 cylinders, while I wait for parts and time, without causing other engine damage?

Post by **Ozark Lee** » 31 Oct 2010, 19:08

The compression readings tend to say a burned valve.

Yank the head and see what you find. Pulling a head is very much like opening a Christmas present - you never know what you will find.

Ya, you can drive it if need be. You aren't helping things but then again I doubt you are hurting anything either. If you go too long you will wind up burning up the Cat due to excessive unburnt fuel through the system but in the short run you should be OK.

...Lee

Post by **jblackburn** » 31 Oct 2010, 19:51

For now, you can unplug the connector to the injector and spark plug; essentially the cylinder will be de-activated. You'll run rough, but you should be able to get back and forth to work ok.

Post by **erikv11** » 31 Oct 2010, 23:32

Thanks, I did unplug the injector connector yesterday but left the plug wire on. It seems to run a lot rougher with the injector shut down, could the cylinder have been firing before, but providing essentially no power?

Time to pull the head and see what's up. Hmmm time ... maybe end of the week.

Post by **erikv11** » 17 Nov 2010, 00:28

An exhaust valve in #1 has a hole in it.

Head is at the machine shop, where they are replacing the valve and all valve stem seals. All the other valves and the rest of the head checked out fine at the shop.

jimmy joe · Post by **jimmy joe** » 17 Nov 2010, 10:36

Can I ask what this is gonna cost?
Did you pull the head yourself?
thanks

Post by **erikv11** » 17 Nov 2010, 12:46

$300 to the shop, but on top of that I provided the valve stem seals (Volvo Brand) and the valve (TRW).
With that plus many incidental parts replacements (head gasket, other gaskets, cylinder head bolts, cam seals, timing belt, cap and rotor, plugs, rad hoses, PCV, battery cable) I'm in for about $600.

Pulled the head myself, first time for me, went fine except for one stubborn head bolt I eventually freed up. We'll see how putting it back together goes but I am not concerned now that I have seen it come apart. There is a lot of good info available here and at volvospeed.com.

You can buy a reman head from Clearwater Heads in FLA for I think $450 exchanged, have only heard good feedback about going that way. Most forums say the price is $350 but their web site says $450, not sure what is up. Anyway I decided to stick with this head because I know the history and could get it done locally at a very good machine shop.

Post by **Ozark Lee** » 17 Nov 2010, 19:37

Anyway I decided to stick with this head because I know the history and could get it done locally at a very good machine shop.

That is always a good plan. If you know absolutely nothing about the car (like the bulk of mine) the Clearwater route might be good but if you have good service records on the car fixing what you have is the best route IMHO.

Let us know how it goes.

...Lee

Post by **erikv11** » 27 Nov 2010, 09:46

Installed the head last night. The 12th (last) bolt was not nearly as difficult to put through the last 130 degrees of the torque sequence.

It didn't squeak at all whereas all 11 of the other ones creaked and/or popped at least a little and I had to really crank for the last 30 degrees or so on them. But number 12 was smooth, had to crank but not as hard, was able to move right through the 130 degrees. Makes me wonder if something is wrong there. This is NOT the bolt that was stuck.

Should I just move on no worries, or do I need to do something about that? Kinda stuck here, not sure if I can take it back out and try again or if that would even help, but would hate to not get a good head gasket seal ...

Post by **Ozark Lee** » 27 Nov 2010, 10:23

If the bolt is seated I would just move on but if it didn't act like it went in as far as the others you might have some residual coolant in the bolt hole that is preventing the bolt from seating all the way.

Coolant in the bolt hole will keep the bolt from seating but it will torque down.

...Lee